<template>
  <el-select
      class="bjs-input tree-select"
      :disabled="disabled"
      :value="valueTitle"
      :clearable="clearable"
      :hide-on-click="false"
      filterable
      :filter-method="selectFilter"
      @clear="clearHandle"
      @visible-change="treeTextClear"
      ref="rootSelect">
    <el-option :value="valueTitle" :label="valueTitle">
      <el-tree  id="tree-option"
                class="tree-tree"
                ref="selectTree"
                :accordion="accordion"
                :data="options"
                :props="props"
                :node-key="props.value"
                :default-expanded-keys="defaultExpandedKey"
                :expand-on-click-node="false"
                :default-expand-all="true"
                :filter-node-method="filterNode"
                @node-click="handleNodeClick">
      </el-tree>
    </el-option>
  </el-select>
</template>
<script>
export default {
  name: 'el-tree-select',
  props:{
    /*================================================================
     *  配置项
     *================================================================*/
    props:{
      type: Object,
      default:() => {
        return {
          value: 'id',         // ID字段名
          label: 'title',      // 显示名称
          children: 'children' // 子级字段名
        }
      }
    },
    /*================================================================
     *  选项列表数据(树形结构的对象数组)
     *================================================================*/
    options:{
      type: Array,
      default: () => {return []}
    },
    /*================================================================
     *  初始值
     *================================================================*/
    value:{
      type: Number,
      default: () => {return null}
    },
    emptyString:{
      type:Boolean,
      default: () => {return false}
    },
    /*================================================================
     *  可清空选项
     *================================================================*/
    clearable:{
      type:Boolean,
      default:() => {return true}
    },
    disabled:{
      type:Boolean,
      default:() => {return false}
    },
    /*================================================================
     *  自动收起
     *================================================================*/
    accordion:{
      type:Boolean,
      default:() => {return false}
    }
  },
  /*================================================================
   *  框中显示的数据
   *================================================================*/
  data () {
    return {
      treeText: '',
      valueId:this.value,    // 初始值
      valueTitle:'',
      defaultExpandedKey:[]
    }
  },
  watch: {
    value () {
      this.valueId = this.value
      // 初次初始化时可能树状列表数组尚未赋值
      setTimeout(() => {
        this.initHandle()
      },50)
    },
    emptyString () {
      if (this.emptyString) {
        this.clearHandle()
      }
    },
    treeText(val) {
      this.$refs.selectTree.filter(val);
    }
  },
  methods: {
    /*================================================================
     *  初始化
     *================================================================*/
    initHandle () {
      if (this.valueId) {
        let node = this.$refs.selectTree.getNode(this.valueId)
        if(node != null) {
          this.valueTitle = this.$refs.selectTree.getNode(this.valueId).data[this.props.label]     // 初始化显示
          this.$refs.selectTree.setCurrentKey(this.valueId)       // 设置默认选中
          this.defaultExpandedKey = [this.valueId]                // 设置默认展开
        }
      } else {
        this.valueTitle = ''
        this.treeText = ''
      }
      this.$nextTick(() => {
        let scrollWrap = document.querySelectorAll('.el-scrollbar .el-select-dropdown__wrap')[0]
        let scrollBar = document.querySelectorAll('.el-scrollbar .el-scrollbar__bar')
        scrollWrap.style.cssText = 'margin: 0px; max-height: none; overflow: hidden;'
        scrollBar.forEach(ele => {
          ele.style.width = 0
        })
      })
    },
    /*================================================================
     * 切换选项
     *================================================================*/
    handleNodeClick (node) {
      this.valueTitle = node[this.props.label]
      this.valueId = node[this.props.value]
      this.$emit('getValue',this.valueId)
      this.defaultExpandedKey = []
      this.$refs.rootSelect.blur()
    },
    /*================================================================
     * 清除选中
     *================================================================*/
    clearHandle () {
      this.valueTitle = ''
      this.treeText = ''
      this.valueId = null
      this.defaultExpandedKey = []
      this.clearSelected()
      this.$emit('getValue',null)
    },
    treeTextClear (flag) {
      if (flag)
        this.treeText = ''

    },
    /*================================================================
     * 清空选中样式
     *================================================================*/
    clearSelected () {
      let allNode = document.querySelectorAll('#tree-option .el-tree-node')
      allNode.forEach((element) => element.classList.remove('is-current'))
    },
    filterNode(value,data) {
      console.log(data)
      if (!value) return true;
      return data.name.indexOf(value) !== -1;
    },
    selectFilter (value) {
      this.treeText = value;
    }
  },
  mounted () {
    this.initHandle()
  }
}
</script>
<style scoped lang="scss">
  .tree-select {
    /deep/ .el-select-dropdown__list {
      @include b_color();
    }
  }

  .tree-select /deep/ .el-input__inner:focus {
    @include b_color();
  }

  .tree-select /deep/ .el-input__inner:hover {
    @include b_color();
  }

  .tree-tree {
    @include bg_color();

    /deep/ .el-tree-node__content {
      height: 23px !important;
      &:hover {
        [data-theme="night"] & {
          background-color: $theme-color-night-dark-3;
        }
      }
    }
    /deep/ .el-tree-node__label {
      font-size: 14px;
    }
    /deep/ .el-input__inner {
      border-color: $theme-color-night-dark;
    }
  }
  .el-scrollbar .el-scrollbar__view .el-select-dropdown__item{
    height: auto;
    max-height: 274px;
    padding: 0;
    overflow: hidden;
    overflow-y: auto;
  }
  .el-select-dropdown__item.selected{
    font-weight: normal;
  }
  ul li >>>.el-tree .el-tree-node__content{
    height:auto;
    padding: 0 20px;
  }
  .el-tree-node__label{
    font-weight: normal;
  }
  .el-tree >>>.is-current .el-tree-node__label{
    @include color();
    font-weight: 700;
  }
  .el-tree >>>.is-current .el-tree-node__children .el-tree-node__label{
    color:#606266;
    font-weight: normal;
  }
  .el-tree /deep/ .el-input__inner {
    @include b_color();
  }

</style>
